Method of making profiled rails and bodies composed thereof

ABSTRACT

A method of forming sharp-edged profiled rails and bodies from metal bands. A band is first corrugated, and a directrix is determined subdividing the band into first and second areas composed of the areas between the first and second exterior edges of the band and the directrix. One of the areas is moved in a swinging motion about the directrix while the transverse distance of the associated exterior edge of the area from the directrix is reduced during each part of the continuous forming process. By continuously reducing this transverse distance accrued edge tensile stresses are reduced. The initial corrugations formed in the band are increased so that the length of each envoloping line of each part of the band is longer than the enveloping line of the longitudinal profile contemplated for the corresponding part by about 2-5 percent. This allows subsequent upsetting and bending of the band with a curvature smaller than the band thickness without any thinning or weakening at the bends. Profiled rails formed in this manner may then be connected to form profiled bodies in a variety of ways.

United States Patent 1191 Falkner et al.

14 1 Oct. 15, 1974 1 1 METHOD OF MAKING PROFILED RAILS AND BODIESCOMPOSED THEREOF [73] Assignee: RAPENA Patentand Verwaltungs-AG, Vaduz,Liechtenstein 221 Filed: Jan. 16, 1973 21 App]. No.: 324,213

[30] Foreign Application Priority Data Primary liruminer-Milton S. MchrArmrney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT A methodof forming sharp-edged profiled rails and bodies from metal bands. Aband is first corrugated, and a directrix is determined subdividing theband into first and second areas composed of the areas between the firstand second exterior edges of the band and the directrix. One of theareas is moved in a swinging motion about the directrix while thetransverse distance of the associated exterior edge of the area from thedirectrix is reduced during each part of the continuous forming process.By continuously reducing this transverse distance accrued edge tensilestresses are reduced. The initial corrugations formed in the band areincreased so that the length of each envoloping line of each part of theband is longer than the enveloping line of the longitudinalprofile'contemplated for the corresponding part by about 2-5 percent.This allows subsequent upsetting and bending of the band with acurvature smaller than the band thickness without any thinning orweakening at the bends. Profiled rails formed in this manner may then beconnected to form profiled bodies in a variety of ways.

8 Claims, 26 Drawing Figures PATENTED BET 914 SHEET 50F 7 METHOD OFMAKING PROFILED RAILS AND BODIES COMPOSED THEREOF The present inventionrelates to a method of making profiled rails and bodies composed thereofby means of the continuous forming of metal bands. Such forming iseffected by rotating roll forming tools between which the said metalbands are passed. Such roll forming operations for making profiled railsare generally known and so are the roll forming machines employedtherefor. Forming of the flat metal band involved is commonly effectedin a large number of consecutive forming steps each between a rotatingpair of rolls so that the mechanical stress applied to the material ineach forming step will not exceed the admissible maximum value in orderto prevent excessive stretching and weakening at the bends and theappearance of longitudinal cracks. A known measure to avoidoverstressingthe material during forming consists of first corrugatingthe metal band in individual areas in order to facilitate subsequenthollow forming at the points involved by the provision of a sufficientquantity of material.

With the knownmethods of roll forming it has already been possible toproduce comparatively complex hollow structures in a continuously movedmetal band. However, the general rule here is that the metal band is atno point in forming bent with a radius of curvature smaller than theband thickness. Only then can it be en- 'sured in the conventional rollforming process that inadmissible weakening of the material is reliablyavoided. The observance of this generally recognized rule has for anatural consequence that the profiled rails made by roll forming haveonly rounded and not square sectional structures and clearly distinguishthemselves from the extruded sectional rails provided with sharp-edgedprofiles. 7

Since sharp-edged extrusion-formed rails are preferred, despite thehigher price, for many'uses, such as for window and door frames, it isdesirable to improve the methods and economics of roll forming so thatcomparable sharp-edged profiled rails can be formed. The methodaccording to this invention constitutes a solution of this problem andrelates to making profiled rails and bodies composed thereof by thecontinuous forming of metal bands which are passed between rotatingpairs of forming rolls and first corrugated in certain areas tofacilitate the subsequent profiling operations. This method ischaracterized in that a directrix is determined on the metal band whichcoincides with a marked longitudinal edge of the finished profiled railsand that the first area of the metal band extending from theone exterioredge to the directrix is largely held in the initial position during thesubsequent forming steps, while the second area extending from the otherexterior edge to the directrix is tur-ned'about the directrix away from.the initial position during the consecutive forming steps while thesaid exterior edge performs a swinging motion and the edge tensilestress there obtaining is reduced, that the initial corrugations areincreased until their enveloping lines transversely to the metal bandbecome longer than the enveloping line of the longitudinal profilecontemplated in the area involved and that, at the bending points of therails, the band is upset transversely to the direction of travel byusing thesurplus width created by the corrugations, bent with a radiusof curvature smaller thanthe band 'thickness'and formed into sharp-edgedprofile structures.

The method according to the invention will now be described in greaterdetail with regard to exemplified embodiments with reference to thedrawing, FIGS. 1 through 15, in which FIG. 1 is a diagrammatic view ofthe consecutive forming steps in the metal band in making a complexrail, and the contemplated rotation of the basic plane;

FIG. 2 is a cross-section of the completed rail made by the formingsteps of FIG. 1;

FIGS. 3 through 15 show pairsof rolls, partly at a reduced scale andpartly in natural size, for the performance of forming steps in themaking of the sharp-edged profiled rail according to FIG. 2;

FIG. 16 shows a profiled hollow body with folded welts made with therail according to FIG. 2;

FIGS. 17 through 19 show further exemplified embodiments of hollowbodies with folded welts between two pairs of rails, and

bodiments of hollow bodies with welded joints between a pair of rails.

The present method will now be described in conjunction withthe formingof a flat metal band into a profiled rail provided with grooves, whichis shown in cross-section in FIG. 2. It is obvious that a rail profiledwith such sharp edges can be produced by extrusion but not by themethods of roll forming'so far known. The production process of thisprofiled rail according to the present method is shown diagrammaticallyin FIG. 1', the metal band 10 having the dot-dashed crosssectionalconfiguration at the points A, B, C M, ,N,

' To begin with, a directrix 1'] is determined in the horizontal initialposition'A of the metal band 10, the said directrix corresponding toa-particularly marked longitudinal edgeof the finished profiled hollowrail, in the present case the exterior edge 11 in FIG. 2. The horizontalarea 11-12 of the metal band 10 extending between the exterior edge l2of the band 10 and the directrix 11 is to remain largely in thehorizontal initial position inthe present example, with the exception ofthe longitudinal border 14 which is bent upwards in the course of theforming operation (cf. point 0). This first area 11-12 comprises thelongitudinal border 14, the side wall 15 and the boundary 16 of thelongitudinal groove 17 includingits sharp-edged'flanges. As indicated inFIG. 1 at the point 0, the directrix 11 will fi nally form one, of thelongitudinal edges of the com pleted profiled rail. In the initialpositionA, the. first area 11-12 of the metal band- 10 is substantiallyless widethan the area 11 13 extending from the directrix l1 totheexterior edge 13. In the course of forming, this entire secondat'eall-ISof the metal band 10 is turned in the clockwise direction about-thedirectrix and forms, with of angle against the initial position, theupper side 18"and the double-walled web '19 and, with degrees of angleagainst the initial position, the side wall 20 and thelongitudinal-border 2l'of the completedprofiledrai l. I

In making the sharp-edged bends as at the groove 17 of the rail, thewell-known difficultyarisesv that, owing to the great difference betweenthe inner and the outer radii, theweb of materialunderg'joes stretchingat these points so that the material is thinned, which results inweakening. In the present method these difficulties are overcome bysufficiently strong corrugations. While FIGS. 20 through 26 show furtherexemplified em- I the front side of the flat web of material still formsa straight line A at the beginning of the forming process, the web isfirst given a certain concave and/or convex curvature indicated at B.Such a curvature as the first step of formation is advantageous becausethe transverse stiffness of the web of material is thus reduced and itsresistance against the subsequent forming in the continuous passagebetween corresponding pairs of rolls lowered. The subsequent formingsteps to the point C are designed to produce indentations andconvexities in the web of material at the points where the groovedesignated at 17 in FIG. 3 will subsequently be formed. The indentationsand convexities and, respectively, corrugations are so increased thattheir enveloping line is longer than the enveloping line of the profilethere contemplated. At point C the convexity there designated at 22, ofwhich the enveloping line which extends from about the beginning of theconvexity at point 23 to the end of the convexity at point 24, must belonger than the enveloping line between the points and 26 of the U-typechannel 27 of the profile at point B. Further forming will then produce,from this presently U-type channel 27, the groove designated at 17 inFIG. 2. With a groove 17 of the present configuration, i.e., withsharp-edged bends 28 and 29, it is of advantage to enlarge the convexity22 (point C in FIG. 1) in such a manner that the enveloping line betweenthe points 23 and 24 is longer by 2 to 5 percent than the envelopingline between the points 28 and 29 of the groove 17 (FIG. 2) so that nothinning but a condensation of the wall thickness at the points 28, 29(FIG. 2)

is obtained when the U-type channel 27 (point B, FIG. 1) is upset.

This transformation of the U-type channel 27 between the points E and Lto form the groove 17 with its largely final shape is effected by anupsetting process according to the present method. Appropriatelyprofiled co-operating pairs of rolls are preferably employed for thepurpose, thesaid rolls at the same time reducing the depth of thechannel 27 to the prescribed depth of the groove 17 and thus cause thefolding back at the points 28, 29 and the compressionof the same. Inthis upsetting operation no change in the width of the metal band to theleft and to the right of the points 23, 24 occurs during forming betweenthe points C and L.

In the forming steps leading to the cross-sections D, E and F of themetal band 10 the subsequent longitudinal groove 17 is on the one handprepared in the first area 11-12 and, on the other, the folding for thelater I80 bend ofthe double-walled web 19 begun. In the forming steps 6through L only the final formation of the longitudinal groove 17 isperformed in the. area "-12 and then'the longitudinal border 14 is bentup vertically relative to the side wall in accordance with thecross-sections M, N and 0. On the other hand, the

second area 11-13 of the metal band 10 isso formed in the steps G, H,I,K and L and the 180 bending of the double-walled web 19 is completed onthe one hand and, in'addition, thegradual bending of the upperside 18about the directrix 11 is effected. At the same time the side wall 20vertical relative to. the web' 19 is straightened and the longitudinalborder 21 bent downwards relative to the side wall 20 by 90. Theprofiled rail finally has the cross-section as per FIG. 2 at. the point0.

Also for the complex forming steps contemplated in the second area11-l3, sufficiently pronounced corrugation is produced according to thepresent method in the forming steps B, C, D so that the enveloping linefrom the directrix 11 to the exterior edge 13 in FIG. 1 is longer thanthe enveloping line from the edge 11 to the exterior edge 13 of thelongitudinal border 21 of the completed rail according to FIG. 2.

In making rails with sharp-edged profiles according to the presentmethod it is therefore necessary first to determine the length of theenveloping line on the cross-sectional representation of the desiredrail, advantageously the length of the center line between the outer andthe inner wall of the rail. The width of the metal band is then sodetermined that, with all profile structures and sharp bends, the lengthof the center line there is extended by 2 to 5 percent and the lengthsof the straight portions of the center line are added to these values.This ensures that sufficient width of the metal band is available at thepoints subsequently subject to profiling steps in order to enabletheheavy deformations with upsetting and condensation of the band materialto be effected.

As experience has shown, the upsetting process described enablesmechanically perfect and sharp-edged longitudinal profiles with closelyspecified dimensions to be produced in only a few forming steps, theselection of the length of the indentations and convexities providingthe possibility of obtaining a thickening of the material and astructural condensation at the points desired. The upsetting process isadvantageously performed with profiled engaging pairs of rolls. FIGS. 3through' l5'each show an exemplified embodiment of such engaging pairsof rolls for making a sharp-edged profiled rail as per FIG. 2.

The flat metal band 10 is first formed, possibly following pretreatment,between rotating pairs of rolls with horizontal axes in the manner shownin FIGS. 3 to 5. The convexity designated at 30serves for the productionof the later longitudinal border 14 of the side wall 15 and theconvexity 31 for the preparation of the longitudinal groove 17. On theother hand, the convexities 32 and 33 serve for the preparation ofthe'web 19 and the later longitudinal border 21 of the side wall 20. Aspreviously mentioned, these convexities are designed to providesufficiently wide portions of the band for the subsequent heavy-deformation with simultaneous upsetting.

In the pairs of rolls according to FIGS. 6, 7 and 8 the forming of theconvexity 31 into the groove 17 is indicated, theupsetting'action atthetwo edges 28 and 29 of this groove 17 being clearly visible in theupsetting operation between the pair of rolls according to FIG. 8.Deflection of the band to the left is prevented particularly by the factthat it is held immovable both at the I outer edge of the longitudinalborder 14 and in the area of the sidewall 15 between appropriate rolls.In addition, the flat upper side 18 of the rail and the upper portion ofthe horizontal web 19 are prepared as well as the future longitudinalborder 21 between the pairs .of rolls according to FIGS. 6,7 and 8. a

Between further pairs of rolls according-toFIGS. 9

. through 12 the horizontal double-walled web 19 is first completed andthe profiling of the rail subsequently completed between the pairs ofrolls according to FIGS. 13 through 15. As can be seen from the saidFigures, the plane of the metal band previously arranged virtually inthe horizontal is gradually rotated by 90 of angle. The bend 34 of 180of angle at the outer end of the horizontal web 19 is changed, in thepassage between the pairs of rolls according to FIGS. 10, 11, 12, fromthe rounded shape still shown in FIG. 9 into a more and more rectangularconfiguration, upsetting and material condensation occurring at the sametime without which such a sharp-edged bending operation by 180 degreesof angle would not be possible. In the passage between the pair of rollsaccording to FIG. 15 the profiled rail obtains its final shape as perFIG. 2.

During the heavy deformation just described, which is effected with thesimultaneous upsetting of the material for the creation of sharp-edgedbends and profile structures, substantial tensile stresses occurparticularly in the area of the outer edge 13 of the metal band 10. Inorder to control these tensile stresses andv to avoid both excessivelongitudinal stretching and tearing of the metal band transversely toits direction of travel, the twisting motion in the area 11-13 of themetal band described with reference to FIG. 1 is employed. By utilizingthis twisting motion, the rectilinear distance between the directrix l1and the outer edge 13 of border 21 is gradually reduced resulting inreduction of the marginal tensile stresses.

In the exemplified embodiment, described with reference to FIGS. 1through 11, of forming a metal band into a rail of complexcross-section, it has been assumed that the twisting of the area 1 l-l3relative to the directrix is effected in the clockwise direction. If desired, it would naturally be possible to effect twisting about thedirectrix 11 in the opposite direction so that the underside of themetal band 10 would then become the outside of the completed profilerail according to FIG. 2. At all-events, the present method for extremeroll forming is not limited to the exemplified'embodiment according toFIGS. 1 and 2. Y

In the present method, forming and upsetting of the metal bands iseffected, as described above, by the interaction of pairs of rollsarranged on parallel horizontal shafts and rotating during the passageof the metal band involved. For reasons well known, which areexplained,by way of example, in applicants US. Pat. No. 3,689,970 it is ofadvantage if the metal band is under a mechanical tensile stress in thelongitudinal'direction as it passes the consecutive pairs of rolls. Inthe said known process this tensile stress is created in that the metalband is gripped at its formed end and pulled through all consecutivepairs of rolls while all feeding force is avoided. Since an upsettingeffect is exercised on the passing metal band besides the normal formingprocess in many of the consecutively a rranged'pairs of rolls-accordingto' the present" method, the necessary tractive forces are too high' tobe added and provided by a single tractive devicelocated at the formedend since th'i'swould entail the hazard that the band breaks. On theother hand it must be avoided that a thrusting force is exercised on thepassing metal band assuch is normally the case in pairs of rolls whichare driven individually or jointly. In the present method the problemwas solved -by ensuring that the consecutive pairs of rolls, while beingdriven individually or jointly on the one hand, on the other hand have:their effective diameters gradually enlargedby a'certain percentage sothat the determinative circumferential speed of a'following pair ofrolls is somewhat higher than that of the preceding pair of rolls. Thepassing metal band is thus subject to a longitudinal tension which isnewly built up in each pair of rolls and prevents the development of athrusting force acting onthe band surface;

Suitable dimensioning of consecutive pairs of rolls with increasingcircumferential speed makes it possible to exercise the desirablelongitudinal tensile stress on the passing metal band, to avoid theundesirable thrusting' forces on the band surface and nonetheless toavoid all detriment to the band surface by the tractive forcesof theroll surfaces which pull it. By way of example, it was found that withpairs of rolls with a diameter of about 220 mm on an average of theeffective roll surfaces, an increase of this diameter by increments of0.4 percent in consecutive pairs of rolls produces an increase in thecircumferential speed which supplies an adequate tractive force forpulling the metal bands through the pairs of rolls, which areadditionally driven, even if an upsetting process occurs in forming themetal band in such a pair of rolls. No adverse effects on the surface ofthe metal band can be discovered and chatter marks or other marks do notappear. On the other hand it was found that an increase in the diameterof the effective roll surfaces by only 0.05 percent is not adequate toobtain a sufficient tractiveforce.

. EXAMPLE For making a sharp-edged profile rail according to FIG. 2 analuminium metal band'of'I-.75 mm thickness'(tolerance +0.05 or 0.1 mm)of the AlMg 2.5 alloy (DIN Standards 1725-1 or 1745-1, 2 or 3and 1784-1respectively) was used'in the soft F 18 -22-quality with a mill-finishsurface. The metal band was 232 mm wide. At a cross-section of thecompleted rail made 'in accordance with .the present method, the actuallength of 223.5 mm. was

' measured along the centre line between the outer side andthe innerside. Accordingly upsetting and material condensation in forming wascaused in the magnitude of 232 2235 8.5 mm. 'Upsetting thus amounts toapprox. 3.5 percent in this rail.

It is naturally possible to employ qualities and dimensions of aluminiumbands as well as of bandsmade of metals other than the abovementionedqualities in forming according to the present method. By way of example,sharp-edged profile rails may be made of highgrade steel, preferably ofbands made of the material as per No. 4301 DIN Standards 17006 of thequality 5 Cr Ni 18-9, corrosion and acid-proof, cold-rolled (process IIIc/d), brushed, with a band thickness of 0 .9 to 1.1

The present method has above been described with reference to mak'ingasharp-edged profile rail accord ing to FIG. 2. Rails'with sharp-edgedprofile contours of virtually any configuration maybe made ofa flatmetal band by roll' forming 'according'to' this method,

and -a number of exemplified .embodiments will be described thereforbelow. Inaddition,the presentmethod is however particularly suitable formaking bodies composed of two or more such profiled rails, and inparticular it enables sharp-edged'hollow bodies to be made bysimultaneousiand-continuous 'roll forming two or more metal bands.Forthis purpose each vof the metal bands is passed through a separateset of pairs of forming rolls, profiled in consecutive forming stepsfrom the initial position and the two profiled tails are then placed ina predetermined position relative to one another and then indetachablyassembled into a unitary body.

By way of example, in parallel with making the sharpedged profile railaccording to FIG. 2 in the manner described in great detail above, asecond metal band can be passed through an appropriate number ofseparate pairs of rolls so as to make a second profile rail whichenables a profiled hollow body according to FIG. 16 to be made of thecompletely profiled first rail according to FIG. 2. In this exemplifiedembodiment the second rail consists of the flat bottom 35 and the twolongitudinal borders 36 and 37 at first bent at 90 of angle relative tothe bottom 35. Upon completion of the first profile rail in the pair ofrolls according to FIG. the second rail has its bottom 35 forced againstthe longitudinal borders l4 and 21 respectively of the first rail, andthe longitudinal borders 36 and 37 of the second rail are bent aroundthe longitudinal borders 14 and 21 respectively of the first rail duringthe passage between appropriately designed additional pairs of rolls sothat a folded welt connection of the associated longitudinal borders ofboth rails is obtained. As explained above in the context of making thefirst rail, preferably a sharpedged profile of the bend of thelongitudinal borders 36, 37 of 180 of angle is created in the process sothat sharp-edged outer profile edges are formed at the said point. Informing the second rail the metal band must first be corrugated also forthe second rail so as to enable the material to be condensed during thesharpedged bending and upsetting operation. Again, the necessary widthof the second metal band is greater by 2 to 5 percent than the length ofthe enveloping line, measured between the outside and the inside of themetal band, of the completely formed second rail assembled with thefirst rail. If desired, the folded welt connection between thelongitudinal borders l4 and 36 and 21 and 37 respectively may, duringassembling the first and the second rail for the obtention of thesharpedged profile hollow body according to FIG. 16, be reinforced interms of strength and anchorage by suitable means. Such means are, byway of example, roughing the longitudinal borders 14, 21' and the insideof the longitudinal borders 36 and 37; in addition, suitable adhesivesmay be employed or an additional connection between the longitudinalborders 36 and 14 and 21 and 37 respectively provided by spot welding.

A further exemplified embodiment of a sharp-edged hollow profile bodycomposed of two rails is shown in FIG. 17. The bottom rail 40 isconnected with a symmetrical hat-type rail 41 by folded welts at thecommon longitudinal borders so that a symmetrical hollow'body is formed.Another exemplified embodiment of a sharp-edged hollow, profile bodymade according to the present method is shown in FIG. 18 with the twononsymmetrical rails 42 and 43 which are also interconnected by foldedwelts on the two associated longitudinal borders. The embodimentaccording to FIG.1"19 shows a hollow body made of the rails 44 and 45connected by two folded welts; apart from the sharp-edged profilestructures made in accordance with the present method, dull-edgedprofile structures are shown at, the groove 46 whichmay naturally alsobe produced in processing metal bands according to 3 the present methodif desired. g

In making sharp-edged profile bodies composed of two or more sharp-edgedprofile rails produced according to the present method, the connectionmay be effected not only by foldedwelts as described above withreference to FIGS. 16 through 19. In many cases it is simpler to connectthe individual rails by means of a welded connection. In this case twoprofiled rails have their front faces forced together along two of theirlongitudinal borders and welded along these seams, it being possible toupset this seam in the known manner if desired. Welding may be effectedwith direct, lowfrequency or high-frequency current, if necessary alsoin an inert gas atmosphere. Welding is performed continuously during thepassage of the rails to be connected by means of a suitable weldingapparatus. Such welding apparatus are known and require no detaileddescription. If the welding seam is upset during the welding operation,the material projecting beyond the surface of the welded longitudinalborders must be removed and the sharp-edged profile body so madeadvantageously recalibrated. FIGS. 20 through 23 show exemplifiedembodiments of sharp-edged hollow profile bodies which consist of tworails simultaneously produced by roll forming in accordance with thepresent method and are welded together along two seam lines. The tworails are made simultaneously in a twin machine with appropriate pairsof rolls in such a manner that, when emerging from the last pair ofrolls, the two profiled rails face each other with the front edges ofthe associated borders to be welded and pass into an appropriate weldingapparatus together for the simultaneous welding of the two front edges.In the case of the hollow body according to FIG. 20, the first rail 47is welded to the second rail 48 at the points designated at 49 and 50respectively. In the embodiment according to FIG. 21 the first rail 51is welded to the second rail 52 along the longitudinalseams 53 and 54respectively. The hollow body according to FIG. 23 is formed bywelding-the first rail 59 to the second rail 60 along the welding seams61 and 62 respectively.

Further exemplified embodiments of sharp-edged hollow profile bodieswhich can be made in accordance with the present method are shown inFIGS. 24 through 26. The body according to FIG. 24 is made by weldingthe first rail 63 to the second rail 64 along the welding seams 65 and66. In the case of the hollow body comprising the profiled rails 67 and68 according to FIG. 25, connection is effected by the welding seams 69and 70 respectively. The flat hollow body according to FIG. 26 is formedby the two sharp-edged profile rails 71 welded together along the seams73 and 74.

It can be seen from the exemplified embodiments of bodies that are madeby assembling sharp-edged profile rails as briefly described withreference to FIGS. 16 through 26, that the present method enables anybodies provided with complex longitudinal sections to be made in onlyone operation and in continuous production.- Obviously not only hollowbodies can be'made in this. manner but also double-walled rails of'highmechanical strength without an enclosed hollow space, suitableconnection of the adjoining walls by bonding or spot welding enablingthe mechanical strength to be enhanced.

In making sharp-edgedprofiled bodies according to the presentmethod,,two flat bands, as briefly mentioned above, are firstsimultaneously formed into profiled rails in a twin machine by rollforming, placed in the necessary relative position and then undetachablyconnected. It has proved to be of. advantage for the pairs of rolls ofthe twin machine serving to make the complex rail to be jointly drivenwhile the pairs of rolls required to make the less strongly profiledsecond rail are equipped with a separate drive. Naturally this separatedrive concerns only those pairs of rolls for the second band which arerequired for its forming until the two rails are assembled. Thisseparate drive, however, is so designed that an elastically operatingclutch is provided between the pairs of rolls so that the transit speedof the second band and, respectively, the second rail can automaticallyadjust itself to the transit speed of the first rail. This is necessarybecause the first rail with its rigid drive must naturally determine thetransit speed after the two rails are joined and because the drive ofthe second rail must automatically adjust to that transit speed.Suitable elastic clutches, by way of example hydrostatic drives or VOITHturboclutches which are suitable for the present purpose, are generallyknown and need no further explanation.

The present method of sharp-edged roll forming with upsetting andcondensation of the formed metal bands at the bending points is, aspreviously explained, particularly suitable. for making complex profilestructures. In particular, it is possible also to provide exceptionallywide metal bands with a plurality of profiled longitudinal structures byfirst providing appropriate indentations and convexities at individualpoints and then gradually roll forming while the metal band issimultaneously upset. It is thus possible, by way of example, to makethe exemplified embodiments of sharp-edge hollow profile rails shown inFIGS. 20 through 26 of only a single metal band of adequate width and toconnect them along only a single longitudinal seam.

A hollow rail with a cross-section according to FIG. 20 may therefore bemade of only one metal band of appropriate width in that a directrix isfirst selected about where the left-hand'edge of the upper side is to beobtained and by providing sufiiciently deep indentations and/orconvexities in the band at all points'contemplated for profiledlongitudinal structures. These indentations and convexitiesmust have anenveloping line length which is larger by 2 to 5 percent than the meanenveloping line of the profile structures to be made at the pointsinvolved. There follows the step-bystep roll forming of the band, atleast one of its exterior edges performing a swinging motion about thedirectrix while the individual bending and profiling operations areperformed where the metal band is upset. Finally the two front edges ofthe left and of the right border of the metal band face one another atthe point designated at 49 in FIG. and are joined together, by way ofexample by welding. In this manner, a sharp-edged hollow profile railclosed on all sides is thus made of only one metal band. 7 v

In making hollow rails according to the embodiments of FIGS, 20 through26 ofonly one metal band, the necessary single longitudinal seam isadvantageously placed at'a point which is not visible when such hollowrails-are employed. By way of example, inemploying the hollow railaccordingto FIG. 20 as a window or door frame, a longitudinal seam atpoint 49 will not be visible since it is located at the bottom of alongitudinal groove in which a profiled sealing strip of an elasticrubbentype material is inserted.

Weclaim: f I

l. A method of making profiled rails and: bodies composed thereof bycontinuous forming of at least on metal band characterized by the stepsof:

a. introducing initial undulations into parts of said band to facilitatesubsequent profiling of said band- 10 by bending it at bending pointsbetween rotating pairs of forming rolls; I b. determining a directrixsubdividing said metal band into a first area extending from oneexterior edge to said directrix, and a second area extending from theother exterior edge to said directrix, said directrix coinciding with amarked longitudinal edge to be formed into said metal band; c. turningat least one of said areas about said directrix so that the exterioredge associated with said area performs a swinging motion while thetransverse distance of said associated exterior edge from said directrixis reduced step-by-step throughout the continuous forming process,thereby reducing I accrued edge tensile stresses;

d. increasing said initial undulations of said parts of said band untilthe enveloping lines of said parts transverse to said metal band becomelonger than the enveloping lines of the longitudinal profilecontemplated for said parts thereby leaving surplus width, whereby nothinning of the band will occur during subsequent upsetting; and

e. transversely upsetting said metal band at said bending'points usingthe surplus width created by increasing said undulations, and bendingsaid metal band with a curvature smaller than the band thickness intosharp-edged profile structures.

2..A method according to claim 1 further characterized in that alongitudinal tractive force is exerted on said metal band by asubsequent pair of rolls as said metal band passes between at least someof the pairs of forming rolls by the roll surfaces'of said subsequentpair of rolls being driven at a higher circumferential speed than thecorresponding roll surfaces of the preceding pair of rolls.

3. A method according to claim 2 further characterized-in that thecircumferential speed of said subsequent pair of rolls is higher by atleast.0.2 percent that that of the preceding pair of rolls.

4.A method according to claim 1 further characterized in that theenveloping lines of said parts of said metal band resultingfrom'increasing said initial undulations are larger by 2-5 percent thanthe enveloping lines of the longitudinal profile contemplated for saidparts. H

5. A method according to claim 1 further characterized in that first andsecond metal bands are formed simultaneously, -the second metal bandbeing. twisted from its initial position during the continuous forming,profiled, and placed ina predetermined position relative to a profiledrail formed from the-first metal band, and indetachably connected to thelatter to make a profiled body. t

6. Amethod according to claim 5 further characterized in that'afold-type connection'betwe'en both profiled rails is'rnade at theirlongitudinal borders, the longitudinal borders beingforced together andone longitudinal edge of one rail being bentaround-the associatedlongitudinal borderof the other rail, the two longitudinal bordersthereby becoming indetachably interconnected. p

7. A method according to claim 1 further characterized in that saidmetal band is formed into a sharpedged profiled rail having left andright exterior b0rders by said continuous forming'operations, saidprofiled rail having a cross-section corresponding to a hollow rail inwhich said left and right exterior borders of 1 1 12 said metal band areturned to face one another and inrails through a third group of rotatingpairs of formterconnected so that a sharp-edged profiled hollow rail ingr ll f r completing said profiled body, Closed on all Sides with y (me'Ongitudiflal Seam is d. jointly driving said first and third groups ofrotating madepairs of forming rolls with the same speed,

A method of making a Profiled body composed of e. driving separatelysaid second group'of rotating f ifig fiiit metal band by bendpairsfuming mus with. a speed autfmafically ing between a first group ofrotating pairs of fomk ad usted to the speed of said first and thirdgroups of rotating pairs of forming rolls, and

ing rolls thereby fonning said first profiled rail, continuous formingof a second metal band 10 f. connecting said first and third groups ofrotating tween a second group of rotating pairs of forming P of formmgT0115 to Said Second group of rotatrolls thereby forming said secondprofiled rail, ing Pairs of forming T0115 with an elastically p c.connecting said first and second profiled rails, ining Clutch.

eluding by passing said first and second profiled

1. A method of making profiled rails and bodies composed thereof bycontinuous forming of at least one metal band characterized by the stepsof: a. introducing initial undulations into parts of said band tofacilitate subsequent profiling of said band by bending it at bendingpoints between rotating pairs of forming rolls; b. determining adirectrix subdividing said metal band into a first area extending fromone exterior edge to said directrix, and a second area extending fromthe other exterior edge to said directrix, said directrix coincidingwith a marked longitudinal edge to be formed into said metal band; c.turning at least one of said areas about said directrix so that theexterior edge associated with said area performs a swinging motion whilethe transverse distance of said associated exterior edge from saiddirectrix is reduced stepby-step throughout the continuous formingprocess, thereby reducing accrued edge tensile stresses; d. increasingsaid initial undulations of said parts of said band until the envelopinglines of said parts transverse to said metal band become longer than theenveloping lines of the longitudinal profile contemplated for said partsthereby leaving surplus width, whereby no thinning of the band willoccur during subsequent upsetting; and e. transversely upsetting saidmetal band at said bending points using the surplus width created byincreasing said undulations, and bending said metal band with acurvature smaller than the band thickness into sharp-edged profilestructures.
 2. A method according to claim 1 further characterized inthat a longitudinal tractive force is exerted on said metal band by asubsequent pair of rolls as said metal band passes between at least someof the pairs of forming rolls by the roll surfaces of said subsequentpair of rolls being driven at a higher circumferential speed than thecorresponding roll surfaces of the preceding pair of rolls.
 3. A methodaccording to claim 2 further characterized in that the circumferentialspeed of said subsequent pair of rolls is higher by at least 0.2 percentthat that of the preceding pair of rolls.
 4. A method according to claim1 further characterized in that the enveloping lines of said parts ofsaid metal band resulting from increasing said initial undulations arelarger by 2-5 percent than the enveloping lines of the longitudinalprofile contemplated for said parts.
 5. A method according to claim 1further characterized in that first and second metal bands are formedsimultaneously, the second metal band being twisted from its initialposition during the continuous forming, profiled, and placed in apredetermined position relative to a profiled raIl formed from the firstmetal band, and indetachably connected to the latter to make a profiledbody.
 6. A method according to claim 5 further characterized in that afold-type connection between both profiled rails is made at theirlongitudinal borders, the longitudinal borders being forced together andone longitudinal edge of one rail being bent around the associatedlongitudinal border of the other rail, the two longitudinal bordersthereby becoming indetachably interconnected.
 7. A method according toclaim 1 further characterized in that said metal band is formed into asharp-edged profiled rail having left and right exterior borders by saidcontinuous forming operations, said profiled rail having a cross-sectioncorresponding to a hollow rail in which said left and right exteriorborders of said metal band are turned to face one another andinterconnected so that a sharp-edged profiled hollow rail closed on allsides with only one longitudinal seam is made.
 8. A method of making aprofiled body composed of first and second profiled rails by a.continuous forming of a first metal band by bending between a firstgroup of rotating pairs of forming rolls thereby forming said firstprofiled rail, b. continuous forming of a second metal band between asecond group of rotating pairs of forming rolls thereby forming saidsecond profiled rail, c. connecting said first and second profiledrails, including by passing said first and second profiled rails througha third group of rotating pairs of forming rolls, for completing saidprofiled body, d. jointly driving said first and third groups ofrotating pairs of forming rolls with the same speed, e. drivingseparately said second group of rotating pairs of forming rolls with aspeed automatically adjusted to the speed of said first and third groupsof rotating pairs of forming rolls, and f. connecting said first andthird groups of rotating pairs of forming rolls to said second group ofrotating pairs of forming rolls with an elastically operating clutch.